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Junior Data Analyst interview questions shared by candidates

## Top Interview Questions

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Junior Data Analyst was asked...27 August 2013

### For a given array count combination of pairs of (x,y) whose sum is N.

int[] list = {7,6,2,3,4,5}; int N=9; int count=0; for(int i=0;i

Three solutions I gave. 1. Sort the array in O(nlogn). Min and Max as two indices. Count=0 Loop if A[Min]+A[Max]N Decrement (Max) else Increment(Count) End 2. Using extra space and count sort if the minima and maxima of array sets are in a given range. Max absolute negative number subtracted to keep numbers in positive number space. Loop if Memory[N- A[i]- Min] Increment(Count) End 3. Create a Hashset/Hashtable. Look for N-A[i] and increment count if found. Loop if Get(N- A[i]) Increment (Count) else Push(A[i]) End Less

the complexity of ur solution is not so good you can do better

### If a jar has X red balls and Y blue balls, what is the minimum number of draws that is necessary to ensure that you have one ball of each color?

It is max, the first reply was correct. I you have 5 blue balls and 2 red balls : - If it was min : you take 3 balls, it is still possible to have picked 3 blue balls. - with max : you take 6 balls, the worst case is that you have picked 5 blue and 1 red balls. Less

max(X, Y)+1

min(X,Y) + 1 is correct, not max()

### How would you query an SQL database with Tera of data?

Not sure of the answer but would try to partition my query.

I would probably batch my data

48 actually

47

### The details of your past projects

My project is changing detection using Gray level ambiguity optimization. Before earthquake is position condition. And after earthquake is the same position damage of the particula of the situation and damage Less

We can define of the damage position

### Find out whether an array/string contains non-repeated characters.

Two solutions I gave 1. Make a bucket of ASCII (256),/ Eng Alphabet(26)characters.Look for count of A[i] . If 1 return false else return true in the end Loop if (!Memory[A[i]]) ) Increment (Count) else return false End return true 2. Create a Hashset/Hashtable. Look for A[i] . If found return false else return true in the end Loop if ! Get(A[i]) Push (A[i]) else return false End return true Less

the complxity of your solution will be O(n) runtime and O(n) memory you can do better Less

### If the coefficient of an independent variable in linear regression has an opposite sign than it should be, what might be the reason

multicollinearity

### Excel document- recgnize what type of security breach this is...

I didn't figure it out because I never studied this before...I came to interview for a Junior position and the test was senior level. Less